Reduce webkit CSS prefixes in ui/ styles

ui/webui/resources/css/tree.css

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
 tree {
   display: block;
   outline: none;
   overflow: auto;
 }
 
 .tree-item > .tree-row {
   -webkit-user-select: none;
   background-color: rgba(255, 255, 255, 0);
   border: 1px solid rgba(255, 255, 255, 0); /* transparent white */
   border-radius: 2px;
   color: black;
   cursor: default;
   line-height: 28px;
   padding: 0 3px;
   position: relative;
   white-space: nowrap;
 }
 
 .expand-icon {
   transform: rotate(-90deg);
-  -webkit-transition: all 150ms;
+  transition: all 150ms;
   background: url(../images/tree_triangle.svg) no-repeat center center;
   background-size: 8px 5px;
   display: inline-block;
   height: 16px;
   opacity: .6;
   position: relative;
   top: 6px;
   vertical-align: top;
   width: 16px;
 }
@@ skipping 130 matching lines @@
 <if expr="not is_macosx and not is_ios">
   outline: none;
 </if>
   padding: 1px 7px 1px 1px;
 }
 
 html[dir=rtl] .tree-item[editing] input {
   margin: -2px -3px -2px -8px;
   padding: 1px 1px 1px 7px;
 }